How do I make it so something will go when collected, then re-spawn after awhile?
You can toggle objects. 


On request the visible object can remove itself and adds another invisible object that counts the 60s. 

After timeout the invisible object deletes itself and adds the visible object again.



As you can only add objects from an invisible layer and you want to re-add your objects, I suggest to start with an empty that immediately adds the visible object. This "startup" empty is not needed anymore and can end itself too.